Invertase is an important enzyme commonly used in the food industry, especially in the confectioners’ trade. Invertase preparations available on the market contain the enzyme from the yeast Saccharomyces cerevisiae in a liquid form. The search for new sources of invertase and the obtainment of more stable preparations (powders) may favourably increase the offer for the food industry. Lyophilisation, fluid bed drying and even spray-drying are used to obtain powdered enzyme preparations. The objective of the research study was to evaluate the process of invertase biosynthesis by a genetically modified Polish Yarrowia lipolytica strain from glycerol and to produce a powder of this enzyme by spray-drying. The biosynthesis of the enzyme secreted by yeast was conducted in three independent bioreactor cultures (H1, H2 and H3) with glycerol as the main carbon source. In one bioreactor culture there were obtained 15926 to 40710 invertase units (U) of a specific activity ranging 96.8 ÷ 645.6 U/mg of protein. For spray-drying 3690 ml of mixed post-culture liquid was used; its specific activity was 263.4 U/mg of protein. During spray-drying with 1 % of methylcellulose added 198.12 g of powder was collected and its specific activity was 113.4 U/mg of protein. The powdered invertase from Y. lipolytica had lower pH and temperature optima than the native enzyme and was more thermostable. Under the applied conditions of spray-drying the invertase lost 67 % of the activity, thus further research should be conducted into the optimisation of spray-drying parameters.
Yarrowia lipolytica, invertase, spray-drying, biosynthesis